Beyond susceptibility. Behavioural genetics can advance our understanding of psychiatric disorders, but might not meet the expectations for new cures.

Abstract

Understanding how genes influence behaviour is a pressing question in biology that fosters vivid interest and inevitable controversy. Perhaps the thorniest challenge for behavioural geneticists in the past three decades has been the gradual acceptance by the public of the power of genetics to explain human biology, including the ways in which we think and act. This, in turn, has created expectations that genetic research will not only help to diagnose psychological disorders and disease, but also point to new therapeutic approaches. Here, we discuss the validity of behavioural genetics and its capacity to advance our understanding of behaviour, especially with regard to psychiatric disorders, although we also highlight its limitations in meeting expectations for new diagnostics and cures. > …when considering behavioural traits and mental disorders without consistent neurological findings, it has been much more difficult—if not impossible—to identify specific genetic risk factors ![][1] The conceptual framework and the technical tools used to study behaviour have undergone considerable changes, especially in the past 50 years. For a long time, quantitative behavioural genetics tried to dissect genetic and environmental contributions to individual differences in behavioural traits and disorders. In the 1980s and 1990s, advances in molecular genetics drastically simplified the search for the mechanisms of behaviour by examining the effects of specific gene variations within the larger genetic pool. The combination of association studies, in which a known genetic variant is statistically linked to a phenotype in a heterogeneous population sample, and linkage studies, in which chromosome markers spaced along the genome are statistically associated with a phenotype, was a highly successful strategy to link genetic variation causally with behavioural phenotypes. The enthusiasm for this reductive approach triggered the rise of what has been called ‘neurogenetic determinism’, which, driven in part by a fundamentalist ultra‐Darwinism, seeks to explain every aspect of human … [1]: /embed/graphic-1.gif